Once the fertilized egg implants, the placenta starts developing and begins to release hCG in the blood. Some of this hCG is also found in the urine. This generally happens between 6-12 days post ovulation.
The amount of hCG in the urine rises rapidly in the first few weeks of pregnancy, doubling every 2-3 days. The hCG hormone peaks to its highest levels between 8-11 weeks of the pregnancy and then decreases slowly until several weeks after childbirth.
